I have a 1973 coupe, L48, 4-speed. When I purchased it about 10 yrs ago, it was basically stock, but wasn't numbers matching, so I decided to do some upgrades to make it the car I dreamed of in high school. I started with side pipes!
Anyway, a lot of new things have come along since high school, so I added F.A.S.T EFI, electric fuel pump, electric fans, and electric headlights. It also had Vintage Air installed before I purchased it. Just for info, I had a shop install all those things because I'm not very knowledgeable when it comes to auto electrical! (This shop messed me over really bad and I didn't know it until it was too late! They charged me $200 for a 130 amp alternator, which I never got! I really don't know what else I was charged for but never got. I'm learning about the car and checking things as I learn!)




That is really all the upgrades I ever intend to do. I have no interest in some fancy sound system.
But with those upgrades, I figure I need a better alternator. According to my research, my car came with the alternator installed on the passenger side and the A/C compressor on the driver's side; but I'm assuming the PO moved the alternator to the driver's side because he installed Vintage Air, and the A/C compressor is now on the passenger side.
I'm providing this info so I hope you'll have what you need to help me! I'm a dummy when it comes to anything electrical, and auto electrical totally confuses me...and I'd like to upgrade my alternator to a 100 to 120 amp.
As I said, the alternator is now on the drivers side. It's apparently a Delco-Remy, 63A, internally regulated, #1102908 used in late 70's Corvettes.
I'd like to be able to replace it with a decent alternator that's very close to the same setup, preferably unbolt the old and put in the new; but I doubt that will be possible, so as close to "plug and play" as I can get and still have a good higher amp alternator. So I'd like your thoughts on what alternator you think would be the best and easiest to replace it with.
Any help presented in really easy to understand terms would be much appreciated! I'd also appreciate any guidance on wire upgrades during/after the install. I've read about the "Big 3" upgrade until I'm blue in the face, and I'm more confused about it now than when I first started reading about it!
Thanks in advance to anyone who responds!

 

You can switch that out with an updated alternator easily putting out 120 amps. There is some wiring upgrades that must be made. I would go to Mad Electric and read their papers on upgrading. They also sell inexpensive wiring and relay kits. Good luck. Jerry

 

Don't know where you did your research but all C3's had the alternator on the Driver's side and AC compressor on the passenger side.
Have you considered testing the actual alternator output in case the guts have been changed and the stamp is meaningless?

 

I upgraded my 67 chevelle to a 80amp , the size of wire needed was I think 10 or 8ga , to go up to 120+ you need to run a wire the size of a battery cable 4ga , I would stay with a good 63amp alt and leave the wiring alone. Jmo

 

nohurry
Your 73 is probably quite similar to my 68. I first converted it to a 12si 94-amp alternator but there is no benefit to going for the intermediate step.

For either one of these solutions you SHOULD upgrade the lead going from your Horn Relay Bus Bar to the Starter Post with AT LEAST a 6 gauge lead. It's short run from horn relay to the starter post. To keep it simple you can use a 10-gauge Fusible Link for protection. I picked one up a 6-gauge lead at the local boneyard that came with a fusible link....not that it's a big deal either way to solder one on.

ANYWAY-- as far as alternators:

SINCE you want to keep it simple I would recommend going with a 140-amp CS-144. That way all you need is an adapter with the proper resistance to hook up your supposedly 12si-equivalent connector.

IF you want to make it even better then I would recommend a 145-160 amp DR44G..... and all you need is PWM controller (about 20-30 bucks) but you need to do a little wiring.

I also have F.A.S.T EZ-EFI 2.0, electric fuel pump, electric fan, and A/C...... since you are quite similar to me you DO need more than 63 measly amps.

If you are interested in either of those I can share links for doing one or the other.

also---alternator should be on the driver side.

 

I have a 12si in my (white) 80 4-speed, for now. I'd seriously consider the DR44G option, especially if you think you might swap the engine someday. I think all of my other Corvettes and GM trucks have DR44G, or something similar.

Here's the link to the thread @carriljc started:

https://www.corvetteforum.com/forums...xperiment.html

If you are handy with an Arduino, you can DIY the PWM signal. The alternator defaults to 13.8V without a PWM input, which may be fine anyway.

https://github.com/sparcules/DRuino44

 

carriljc

Thanks for your reply. I've read your comments and alt install in other threads.
As far as alt being on pass side, I got that through an AI search....figures the info would be wrong! I thought there might be something changed since the number on the alt isn't listed as being installed in the '73's.
First...is there a range of years or model specific vehicles that I should look at for getting a CS144? Is it better to get new, reman, or could I get one from a boneyard and have it tested? I found an AC Delco CS144, Part #88877260 for a '94-'97 Camaro on Summit for a reasonable price @ 125.00. Will that work?
Second...please excuse my ignorance, but does "starter post" mean the connection on the actual starter, or the connection on the solenoid?
And Three...yes, I'd appreciate any links/help you're willing to give!
Thanks!

 

Sorry Bikespace! I'd probably better not go that route as I have no idea what an Arduino or a PWM is!

 

The large solenoid post

 

nohurry
I would suggest picking one up at a boneyard but just the way you describe your experience with electrical you're probably better off buying something from a store. IF you are willing to go to the boneyard the selection should be quite wide nowadays.

You want to get a cs-144 with the mounting tabs 180° apart with the electricals connections hopefully away from the exhaust.

You can even get one of the 3-legged goofball from transverse engine GMs and mount it--- that's what I picked up just to see if the body would fit in the alternator mount..... then I got it tested and it turned to be in great shape. Those were in a TON of vehicles... you just need to ensure you are getting a CS-144, 140-amp.

If you go to the boneyard then pick the best looking newiest one you see. I would look anyway... especially if you're going to go the boneyard to pick up six feet of 6-gauge lead with a 10-gauge-fusible- link pre-attached (or metric equivalent) just about every newer car should have something like that..... or move on to the next one.

From what you describe I reckon a CS-144 would be your better option to make it as "plug and play" as possible. I really do think the DR44G would be a better option but would require more fabrication.

Here is a link with info for the connector you need to hook up the CS-144.
BUT --- let's ask: Does the 73 have an ammeter? Does the 73 have a "batt" light? If it has an ammeter and does NOT have a "batt" light then the adapter I mention is more than likely correct. If you want to do more ohmeter checks then I can send you a link to verify that but other than that it should work with this:

https://www.corvetteforum.com/forums...lternator.html

You will need to swap over the v-belt pulley but that's no biggie.

 

nohurry
here is a picture of the CS-144 before I replaced it with a DR44G. Note the location of wiring. Plenty of room.

 

so my first question is why??? are you having issues with the charging system and your battery??? a 63A should be fine I would think... if everything is working fine then personally I'd leave it alone...

/jc

 

I have had a CS-144 140 amp alternator on my 78 L-82 4 speed for about 15 years now. The pictures above are early photos before I added to the wiring in the pictures a much heavier welders cable (I believe a 2 0r 4 GA, can't remember) from the alternator to the starter.

The REAL benefit of the CS-144 140 amp alternator is that this heavy duty monster can provide 80-90 amps at IDLE (or more) if required! A typical 12Si GM alternator whether 63, 80, 100 amps, etc requires revs to produce the rated amperage (not very capable at idle), unlike the CS-144 AND the CS-144 stays VERY Cool even when providing high amperage, unlike the traditional 12SI GM alternators. Bottom line is the CS-144 is one of the best alternators GM ever designed and produced...period.

 

carriljc
Thanks again for your response.
There is a small junkyard just a couple miles up the road from me, so I thought I'd go check that avenue first. It sure would be more affordable!
My car has the +/- Battery gauge with a needle, not an idiot light.
BTW, the CS144 can be clocked if I found one that wasn't exactly in the right position, correct?
Just a side comment, it's nice to hear from someone who also has the FAST EFI 2.0! After I had that put in the car, all I heard were comments about the Holley Sniper and FiTech!

 

nohurry
Yeah. I'd look in the boneyard. Don't forget to look at the 3-legged FWD mid 90s cars too. You can lop off the goof-ball 3rd ear or leave it be. That will widen your options..... just ensure it is a 140-amp...they made a bunch of 105-amps and if you're going to do this get the 140-amp. Below is a picture of how they look and you will notice that the 2 main attachment points are 180° apart.
Get the best looking one you see and then you can go get it tested at Autozone, Oreillys, or one of those places. Write down what you get it out of so you can tell the tester ....they have multiple different rigs/connectors for testing different alternators.

If you are going to the boneyard then look for the alternator output lead also. They'll typically be 4 to 6 gauge in most modern cars with those large amp alternators. AND you'll notice that they have fusible links already attached.... and they're cheap there.

I asked one of our members here for a 73 wiring diagram sometime ago so I have one. You do have an ammeter and the wiring is similar to my 68 but your 73 already came with an internally regulated alternator so, after you run your new 6-gauge leaded (with 10-gauge fusible link protection, then your connections should be plug & play after you get the adapter. You can find that connector I mentioned at napa (Part number Echlin EC82) or go on the net find other equivalents.....BUT YOU NEED TO GET THE CORRECT ONE..... per your own writing I would just go to Napa and that exact part number...unless you wanna get adventurous and find a cross-reference. I suspect that this connector would work for you. Let me know if you want the info to do resistance checks to ensure it is correct: https://www.napaonline.com/en/p/ECHE...gQdSKQNpjkaANw

You can see one of those 3 legged goofballs here... at rock auto here: https://www.rockauto.com/en/moreinfo...wzqb2fvg%3D%3D

 

nohurry
How goes your alternator search?

 

When it comes time to wire in your new alternator I would like to suggest that you consider Marine (boat) wire for your Corvette. The marine wire is made up of the tiny copper wires and is way more flexible than ordinary wire can be. If you used standard wire then you will need tools to bend it 90*, the marine wire is very easy to use and is available in various gauges and lengths. I used a #4 Marine cable from the alternator output to the starter motor positive post terminal and I have no problems with the charging of my battery.

Add up the loads of the current drawn for your big accessories and see what the total is. I am using a 105 amp alternator that looks like the standard type and it works fine for a C3 with: EFI, Electric fuel pump, Electric cooling fans, Stereo and last but not least the MSD (ignition system)

I have never had my battery get low with my charging system the way it is. Don't believe that you "Need" a 150-200 amp alternator. The battery in a C3 is roughly between 75 and 100 amp hours at a 24 hour discharge rate. Anything more than your Car "needs" is a waste of time and money and might lead to replacing the battery more often than normal.

It would be great to mount a small solar 5-10 watt (PV) panel on the C3 to charge up the battery. I have one that I plug in when the car is parked and the sun keeps it charged up and ready for action. This way the battery would be able to be 100% charged up and it might last longer. I wish all cars had a solar panel to keep the battery topped off.

 

Thanks for the info! Just curious...what type of alternator are you using? Also, did you upgrade the battery cables between the battery and the starter, or did you just run the charging wire from alt to starter lug?

 

The alternator I am using is a unit that looks like the units originally delivered on our Corvettes. Instead of 63 amps it is 100 amps, the best part is it uses the
same old brackets that came on the car. It looks like this unit at Summit:

You can see this unit on Summit and they are about $140 on Summit for the Powermaster. A great brand...

I also ran a #4 cable from the alternator output to the Starter motor battery posts. Using Marine wire it will be easier to bend and twist.

I was surprised to see a 150 amp output on this type of alternator. Powermaster makes it for $200 and it will use the same brackets that your existing alternator uses.

Putting a fuse inline with the alternator output might be a wise thing to do, I have not done it yet but plan to.

 

FWIW-The CS144 in my previous post fits ALL THE OEM BRACKETS for the 12SI alternator and is superior, by far, to the 12SI OEM alternator, regardless of amps. AS mentioned, again, high output 12SI alternators will struggle at Idle with providing higher amperage AND will run MUCH hotter than a 140 amp CS144 which provides 80-90 amps at idle, barely breathing.

Lastly, just buy a "welders" 4 GA EXTREMELY FLEXIBLE cable to run the to the starter:

Amazon: What ever length you need!

4 AWG Gauge Fully Assembled Battery Cables, 1-15ft Lengths, Positive or Negative Wire, Pure Copper Battery Replacement Cables, Solar Car Truck RV Camper (8ft - 5/16” Lugs, Single Red)

https://alternatorparts.com/

Call them^^^^they will clock it for you and get you the small diode easy to connect with the current wire in line, plug and play.​​​​​​

Do it once, buy the Cs144 140 amp standard amperage alternator..all you will ever need and the last alternator you will buy.